Tetracalcium phosphate (TTCP) is one of the most common starting materials of calcium phosphate-based ceramic bone cement. However, the ceramic bone cement has a critical drawback such as poor mechanical properties and slow setting time. In this study, the thermodynamically unstable tricalcium silicate (C3S) was synthesized and introduced into TTCP-based bone cement to enhance the mechanical and setting properties of the bone cement.
The cement properties and compressive strength of hardened TTCP-cement with the addition of C3S were examined in terms of the contents of C3S and hardener. First, TTCP and DCPD with C3S (0; 5; 10 wt%) were ball milled for 24 hrs and then dried at 60oC for 1 day. The sample powder was mixed with the solution of a hardener (Na2HPO4.nH2O) with various concentrations (0, 0.5, 1.0 mol/L). The hydration of TTCP and DCPD resulted in the precipitation of HA crystallites and is the major driving force of setting for the TTCP-based bone cements. The XRD peaks of the hardened cements were identified as a mainly HA. With the addition of C3S, the cement showed a longer setting reaction time and lower setting temperature. However, the addition of hardener caused a higher setting temperature and faster setting time. The Vicat setting time decreased with the addition of hardener, but showed anomalous results with the C3S content. The incorporation of both hardener and C3S to cements would come with both the increase of mechanical strength and the reduction of setting time. However, the effect of C3S addition was not significant.